Blessed be the Lord who has given rest to His people Israel, according to all that He promised. (I Kings 8:56 ESV)
Rest
Once when I was teaching, I informed the students that they could have a weekend without homework.
When the students arrived on Monday, a few of them were upset with me. Because some had entered the weekend behind in the homework, their parents made them study on Saturday. Another was planning a few days off from school, and had requested the homework ahead of time, and felt obligated to do that homework during the promised work-free days. And even worse, a couple of the students saw me at a school event, and we ended up conversing about school things. In hindsight, they accused me of making them do homework against my promise.
Silly examples, but the fact is, that we cannot guarantee each other rest. In fact, anyone who plans to spend Saturday afternoon watching football, but finds home maintenance necessary knows that rest is not assured. Anyone who realizes that a relaxing evening is usually interrupted by laundry, dishes, or mowing knows that rest is not assured. Anyone who plans a vacation knows that work is always involved.
Rest only comes from Christ. Christ bought our rest via His work on the cross, and it is eternal. Christ offers us rest through faith in Him. Christ guarantees and assures us of rest that only comes when we lean on Him.
We need rest, ever since Adam broke everything. We can only get rest, though, through Christ.